Nowadays, for surgical applications increasingly assistance systems are used comprising a joint arm, which is for example attachable to the slide rail of an operating table. A medical instrument is coupled to the free end of the freely movable joint arm. For example, in laparoscopy, a rigid endoscope provided with an optical system is mounted on the joint arm and oriented such that the surgeon can see into the target region to be examined or to be treated surgically.
In addition to such an assistance system, usually further instruments are used in surgery, which the surgeon or an assistant has to operate manually. An example is a wound retractor which the assistant inserts into the wound and holds with one hand, so that the surgical area remains accessible for the surgeon. Holding the wound retractor is quite exhausting for the assistant, in particular if the wound retractor has to be held in the same position for a longer period of time.